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Full-Text Articles in Mechanical Engineering
Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza
Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza
Dissertations
Electro-hydraulic pressure-control valves are used in many applications, such as manufacturing equipment, agricultural machinery, and aircrafts to name a few. They are often used to actuate hydraulic clutches, such as those found in power shift transmissions. A traditional pressure-control valve with open-loop control algorithm is typically used in clutch applications. This scheme often results in inconsistent or undesirable system behavior due to the nature of open-loop control as well as the nonlinear system dynamics and uncertainties.
In this research two new electro-hydraulic pressure-control valves were designed in order to decouple the valve and control port (hydraulic) dynamics. This was achieved …
Analytical And Experimental Study Of Investment Casting With Laser Stereolithography Models, Wen-Long Yao
Analytical And Experimental Study Of Investment Casting With Laser Stereolithography Models, Wen-Long Yao
Dissertations
This dissertation presents an analytical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography (SLA) patterns. Included in the consideration are the cracking temperature of the ceramic shell, the web link buckling temperature, and the glass transition temperature of the epoxy resin. The hypothesis is that shell cracking will occur when the cracking temperature is lower than the glass transition temperature and the web buckling temperature.
An analytical and experimental study has been conducted, with the cross-sectional area, the span length of the web structure, and the shell thickness being …